Recently, digital video cameras using a large-capacity disk recording medium such as DVD as a recording medium have been considered. There is a high demand for digital video cameras using such a disk recording medium that are capable of recording not only moving pictures but also still pictures separately from the moving pictures and using both the moving pictures and the still pictures.
Conventionally, however, when a moving picture is recorded on a disk medium, the moving picture is recorded in a digital moving picture format devised for moving picture recording, and when a still picture is recorded on the disk medium, the still picture is recorded in a digital still picture format devised for still picture recording. However, recording and reproducing moving pictures and still pictures in the respective different recording formats on the same disk recording medium requires decoders compatible with the respective recording formats.
Taking as an example a case of using DVD as a disk recording medium, when a moving picture is recorded, a digital moving picture format such as DVD Video Format, DVD Video Recording Format or the like using an MPEG (Moving Picture Experts Group) system as a data compression system is used.
When a still picture is recorded, a digital still picture format referred to as JPEG format, DCF (Design rule for Camera File system) format or the like using a JPEG (Joint Photographic Experts Group) system, for example, as a data compression system is used.
Thus, when both moving picture data and still picture data are reproduced from a recording medium on which the moving picture data and the still picture data are recorded in different recording formats in order to obtain the moving picture and the still picture, both a decoder for the moving picture data (MPEG decoder) and a decoder for the still picture data (JPEG decoder) are required.
Hence, when the recording medium on which the moving picture data and the still picture data are recorded in different compression formats is reproduced by a reproducing apparatus including only a decoder for moving pictures, the reproducing apparatus cannot reproduce the still picture data recorded on the recording medium and therefore cannot use the still picture.
It is therefore conceivable that the moving picture data is recorded on the recording medium in the digital moving picture format and that the still picture data is recorded within an MPEG stream using so-called Private Packets defined in the MPEG system or the like so that the still picture data is recorded so as to be mixed in the digital moving picture format.
When the thus recorded still picture data is reproduced, however, a special MPEG decoder that can decode the Private Packets within the MPEG stream as still picture data is required. Therefore, although the need for a still picture decoder is eliminated, a special moving picture decoder capable of decoding Private Packets as still picture data is required, which cannot be said to be a universal solution.
As described in Patent Document 1 (Japanese Patent Laid-Open No. 2002-325227), for example, a system has been devised which creates a recording medium allowing still picture data taken by a digital still camera and recorded on a semiconductor memory or the like in a digital still picture format to be reproduced by, as it were, a general-purpose reproducing apparatus that is not compatible with the digital still picture format.
With the technique described in Patent Document 1, even the still picture data recorded on the recording medium in the digital still picture format can be converted into an I-picture (Intra-Picture) of the MPEG system and then recorded in a digital moving picture format, thus making it possible to create a recording medium allowing the still picture data to be used by a reproducing apparatus having an MPEG decoder.
However, there is a desire for a technique for recording both moving picture data and still picture data onto a recording medium in a form usable by various reproducing apparatus and recording and reproducing apparatus that general users already have on hand, without purchasing a new recording and reproducing apparatus to which the technique described in Patent Document 1 is applied and which has a function of converting from the digital still picture format to the digital moving picture format.
It is accordingly conceivable that when a still picture is taken by using a digital video camera, still picture data is recorded onto a recording medium in the form of an I-picture of the MPEG system from the beginning. In this case, however, a problem arises as to division of an area for recording moving picture data and an area for recording still picture data in the form of I-pictures so that the still picture data in the form of I-pictures is not mixed with I-pictures of normal moving pictures. It is conceivable that this may cause problems such as increase in complexity of various processing for using and managing the still picture data, a sacrifice to some extent of effective use of the recording medium, and the like.
In addition, resolution of the digital still picture format is generally higher than resolution of the digital moving picture format. Thus, when still pictures are recorded onto a recording medium in the digital moving picture format from the beginning, there is no still picture data in the digital still picture format anywhere, and therefore a reproducing apparatus having a decoder for still picture data in the digital still picture format cannot use still picture data in its original resolution.
Further, as described above, in a case of using DVD as a recording medium, DVD recording formats include the DVD Video Format, the DVD Video Recording Format and the like. In the case of using any of the recording formats, there is a desire to record both moving picture data and still picture data with a minimum limitation.
In view of the above, it is an object of the present invention to eradicate the above problems, and provide a recording apparatus and a recording method that can record both moving picture data and still picture data in a form reproducible by various reproducing apparatus.